This invention relates to deflection yokes for cathode ray tubes and more particularly to a high resolution toroidal-wound deflection yoke having front and back crown members affixed to a core member.
Precision and repeatability of wire placement are reasons frequently expressed for the utilization of toroid-wound deflection yokes for cathode ray tubes. Moreover, such precision and repeatability of wire placement is due to numerous features including the employment of front and back crown members affixed to the front and back ends of a core member of magnetic material. Such crown members usually include slots which permit accurate positional location of the wire turns whereupon uniformity of deflection yokes can be repeatedly achieved.
Although deflection yokes utilizing slotted front and back crown members for determining wire turn placement have been and still are extensively employed, it has been found that there are conditions wherein presently known and available structures are inadequate. For example, presently available front crown members include a plurality of wire receiving slots in a plane parallel to and forward of the front end portion of a core member. Unfortunately, such wire-receiving slots include separating ridges which limit the wire-receiving capabilities and inhibit an intimate relationship of the forward crown member and a cathode ray tube envelope. Thus, it is difficult to provide additional wire turns to enhance the capabilities of the deflection yoke without encountering other difficulties.
Specifically, it has been determined that a deflection yoke with an increased ratio of inductance to resistance would have numerous advantages including an increased efficiency capability. Moreover, it would be highly desirable to achieve this increased ratio of inductance to resistance and efficiency without an undesired increase in spacing between the deflection yoke and a cathode ray tube.
One known method for increasing the inductance to resistance ratio of a deflection yoke is to include additional wire turns about the core member. While such a technique provides the desired increased inductance to resistance ratio, it has been found that the number of added turns has been limited because of the space required to provide slots on the front and back crown members. In other words, the slots are formed by ridges therebetween and the thinness of such ridges is obviously limited by the ability of the ridges to withstand deformity. Moreover, the ridges occupy space which, in turn, reduces the number of wire turns which may be utilized or employed.
Another known attempt at increasing the inductance to resistance ratio included the addition of wire turns by stacking or depositing more than one turn in each slot of the front and back crown members. Although such structures do have advantages, it has been found that stacking of wire turns at the front crown member also deleteriously affects the space relationship of the deflection yoke and picture tube and particularly so at the front end of the deflection yoke. Moreover, the ridges employed to separate the wire turns must necessarily extend further forward than previous structures in order to provide a receptacle for the multiple wire turns per slot which further limits both the snugness of fit between the deflection yoke and the cathode ray tube and undesirably necessitates a reduction in the length of the core member which may be employed.